A tire bead is an important structural component of many tires. The tire bead is typically the inner most edge of the inner and outer sidewalls of a tire. When the tire is mounted on a wheel (or rim), these portions of the tire are in direct contact with the wheel (or rim). Particularly in tubeless tires, for example, the tire bead couples with the wheel structure to form an air-tight seal so that an interior pressure chamber may be maintained between the tire and the wheel. The tire may thus be inflated with air, nitrogen, or any other suitable gas, typically via a conventional valve stem. The interior pressure chamber is maintained at a desired pressure, which, in turn, exerts an outwardly directed force against the tire bead to assist in maintaining the air-tight seal.
Due to the strength and rigidity imparted to the sidewalls of many of today's tires, particularly larger automobile and/or truck tires, for example, it is often difficult to mount a tire onto the wheel so that the tire bead properly seats onto or against a bead area to form the air-tight seal. Accordingly, mounting a tire often involves a secondary step of specifically seating the tire bead. One conventional method for seating the tire bead involves using a special pneumatic seating tool that injects high pressure air into a gap between the loose tire and the wheel structure. The sudden influx of pressurized air into the internal pressure chamber forces the sidewalls to quickly expand and/or snap the tire bead into position onto or against the bead area of the tire structure, thus creating the air-tight seal. The internal pressure chamber may then be inflated with air to the desired pressure.
Conventional pneumatic seating tools may rely on a ball valve to discharge pressurized air from a pressurized air tank, for example. However, the motion required to quickly open and/or close these valves often causes the nozzle to lift off of the wheel, resulting in a significant loss of control over the bead seating process. Other conventional pneumatic seating tools automatically discharge a predetermined volume of air in a single blast, regardless of the tire size to seat. Thus, pressurized air is often wasted when these tools are used to seat normal or smaller sized tires, the larger than required volumes of air draining the tank much more quickly than would otherwise be necessary.
It may be helpful to provide a high volume air valve for a tire bead tool that provides a quick and accurate airflow discharge in easily controlled bursts.